Nineteen plain-English guides to UK tax, National Insurance, pensions and student loans, each checked against the official source.
Every calculator on this site answers a specific question with a number. These guides explain the rules behind those numbers, so the result makes sense rather than just appearing.
They're grouped below by topic. Each one is written in plain English, checked against the responsible official body, and updated for the 2026/27 tax year. Where a rule genuinely differs across England, Scotland, Wales and Northern Ireland, the guides say so rather than quietly assuming you're in England. You can read more about how we verify figures in our methodology.
How PAYE works, what your tax code means, and the thresholds that catch people out.
The other deduction on your payslip, and what it actually buys you.
Auto-enrolment, tax relief, consolidating old pots, and how sacrifice schemes work.
Which plan you're on, how interest really works, and when the balance gets written off.
Bonuses, overtime and redundancy, and why the tax on them looks stranger than it is.